Magnetic conveyor system

ABSTRACT

A conveyor system for use in a continuous proofing and baking apparatus. The system has a conveyor chain, having a plurality of links, which moves along a track. Each link supports a product supporting grid, which has four circular rings. Pole pieces are located in at least some of the rings. Each pole piece has a conical section and can move horizontally relative to the grid. A magnet in each pole piece attaches the pole piece to a product pan.

This is a continuation of application Ser. No. 320,492 filed Mar. 8,1989, U.S. Pat. No. 4,972,941, which is a continuation of applicationSer. No. 059,600 filed June 8, 1987, U.S. Pat. No. 4,836,360, issuedJune 6, 1989.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates in general to a continuous proofing and bakingapparatus for use in a bakery. In particular, the invention relates to acontinuous proofing and baking apparatus having an improved conveyorsystem for carrying product pans through the proofing and bakingapparatus.

2. Description of Prior Art

In the commercial baking industry, dough products are exposed to apredetermined temperature and humidity environment to cause the dough torise. Following this proofing operation, the dough products aretransferred to an oven for baking.

The dough products may be conveyed from the proofing apparatus to theoven on a continuous conveyor system. The conveyor system has anelongated track which extends through and between the proofing andbaking sections of the apparatus. A conveyor chain, having a pluralityof links, moves through the elongated track and carries a plurality ofproduct supporting grids. Each product pan is supported by one or moreproduct supporting grids.

As the conveyor chain moves through the proofing and baking apparatus,the track has some straight Portions and some curved portions. As theconveyor chain travels from a straight portion to a curved portion ofthe track, the relative positions of two consecutive product supportinggrids will change. The conveyor system must be able to support theproduct pans, even though the relative positions of the productsupporting grids change.

SUMMARY OF THE INVENTION

The conveyor system of the invention is designed for use in a continuousproofing and baking apparatus. The conveyor system has a conveyor chain,having a plurality of links, for movement through an elongated track.Each of the links of the conveyor chain supports a product supportinggrid. Each grid has at least one circular ring. A pole piece, having aconical section, is located in the ring, so that the pole piece can movehorizontally relative to the product supporting grid.

A magnet is located on the pole piece in order to connect a product panto the pole piece. The magnet attaches to the bottom of the product panand releasably connects the pan to the pole piece.

As the conveyor chain moves around a curve in the elongated track, therelative positions of two consecutive product supporting grids change.The corresponding changes in position between the pole pieces and theproduct supporting grids allow the conveyor system to carry product pansaround curves in the elongated track.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the conveyor system of the invention.

FIG. 2 is a sectional view of the conveyor system of the invention, asseen along lines 2--2 in FIG. 3.

FIG. 3 is a top view of the conveyor system of the invention.

FIG. 4 is a partial side view, partly in section, of a pole piece of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 1 and 2, the conveyor system of the invention includesan elongated track 11. The track 11 has a bottom 13, two sides 15, 17,and two top pieces 19, 21. There is a longitudinal gap 23 between thetwo top pieces 19, 21.

A conveyor chain 25, having a plurality of links 27, is mounted formovement through the track 11. Each link 27 has a first connectionmember 29 and a second connection member 31. A pair of verticallyspaced, parallel, longitudinal plates 33 extend between the first andsecond connection members 29, 31. As shown in FIG. 2, the upper plate 33is located above the gap 23, in order to help keep debris from fallinginto the track 11.

A horizontal roller 35 is mounted between the two plates 33 to keep theconveyor chain 25 centered within the track 11. A pair of verticalrollers 37 are attached to each first connection member 29 to supportthe weight of the conveyor chain 25.

As shown in FIGS. 1 and 2, a product supporting grid 39 is attached toeach first connection member 29. Each product supporting grid 39 has acover member 41, which is bolted to a pair of bosses 43 which extendupward from the first connection member 29.

Each Product supporting grid 39 has a pair of laterally extending rods45. A pair of longitudinally extending rods 47 are connected to each endof the laterally extending rods 45. The ends of each longitudinal rod 47are curved to form a circular ring 49. The four rings 49 are thuslocated on the four corners of the product supporting grid 39.

At least some of the rings 49 contain pole pieces 51. Each pole piece 51has an upper circular portion 53, and a lower conical portion 55. Thecircular portion 53 has a larger diameter than the ring 49, but theconical portion 55 fits within the ring 49.

The pole piece 51 is secured within the ring 49 by locking means, suchas a circular washer 57. The washer 57 may be removable from the lowerend of the conical portion 55, or the washer 57 may have a flat 59 or ashaped notch, so that the washer 57 can be maneuvered through the ring49.

The circular portion 53 of the pole piece 51 contains a ring magnet 61.The portion of the circular portion 53 not occupied by the washer 57 maybe filled in with a compound 63 or covered with a cap. This compoundfiller 63 or cap keeps debris from accumulating within the circularportion 53 of the pole piece 51.

A product pan 65 may be supported by the pole pieces 51. The metalproduct pan 65 is held to the pole pieces 51 by the magnets 61. As shownin FIG. 2, the product pan 65 is not in contact with the lateral orlongitudinal rods 45, 47 of the product supporting grid 39.

FIG. 3 illustrates a portion of the conveyor chain 25 going around acurve in the track 11. Typically, a product pan 65 is large enough to besupported by two consecutive product supporting grids 39. Therefore,pole pieces 51 are located only in the forward pair of rings 49. If asmaller product pan 65 is used, pole pieces 51 may need to be located inall four rings 49 of each product supporting grid 39.

As a pair of product supporting grids 39 enter a curve in the track 11,the rings 49 on the inside of the curve move closer together, and therings 49 on the outside of the curve move further apart. For example,the distance from a pole piece 51 in one product supporting grid 39 willtypically be 12.5 inches from the pole piece 51 in the next productsupporting grid 39. As the product supporting grids 39 enter the curve,the pole pieces 51 on the inside of the curve will move to 11 inchesapart, while the rings 49 on the outside of the curve will move to 14inches apart.

While the rings 49 are moving relative to one another, the magnets 61 inthe pole pieces 51 are attached to the product pan 65, and cannot moverelative to one another. Therefore, the pole pieces 51 must movehorizontally relative to the rings 49. FIGS. 3 and 4 illustrate how thepole pieces 51 move horizontally relative to the rings 49. As theproduct supporting grid 39 enters a curve, and the rings 49 moverelative to one another, a horizontal force will be applied to the polepieces 51. The pole pieces 51 are raised vertically slightly as theconical portion 55 of the pole piece 51 moves up on the ring 49. Thedimensions of the conical portion 55 are such that the pole piece 51 canmove approximately 0.75 inches in any horizontal direction.

When the product supporting grids 39 reenter a straight portion of thetrack 11, the rings 49 move back to the original position relative toone another. The horizontal force on the pole pieces 51 is removed, andthe pole pieces 51 settle back down to their original positions. Theconical portion 55 of the pole piece 51 causes the pole piece 51 toreturn to a centered position within the ring 49.

The conveyor system of the invention has several advantages over theprior art. The product pan 65 is securely fastened to the productsupporting grid 39, and yet no horizontal forces are applied to the pans65 as the pans go around a curve in the track 11. Further, since theproduct pan 65 is supported by the pole pieces 51 there is no frictionagainst the product supporting grid 39.

Only the preferred embodiment of the invention has been shown. It shouldbe understood that the invention is subject to various rearrangements,modifications, and substitutions without departing from the scope of theinvention.

I claim:
 1. A center driven chain conveyor for use in a food processingapparatus comprising:an elongate track; a conveyor chain; drive meansfor advancing the conveyor around a predetermined course including atleast one arcuate section; a plurality of grids coupled to said conveyorchain at predetermined intervals; a plurality of magnets, each of saidmagnets being mounted on one said grid for securing food conveying pansto the grids for transport around said predetermined course, saidmagnets being mounted for limited movement in a horizontal planerelative to said grid.
 2. The conveyor of claim 1 wherein a pair of saidmagnets carried by adjacent grids maintain a substantially constantposition relative to a single product pan retained by said pair ofmagnets as said adjacent supporting grids change position relative toeach other.
 3. The conveyor of claim 1 wherein each said grid comprisesat least one transverse portion extending substantially perpendicular tosaid conveyor chain and at least one parallel portion extendingsubstantially parallel to said conveyor chain, said parallel portionbeing coupled to said transverse portion.
 4. The conveyor of claim 1further comprising magnet retainers for movably retaining said magnetsrelative to said grids.
 5. The conveyor of claim 1 wherein said foodprocessing apparatus comprises a proofer.
 6. The conveyor of claim 1wherein said food processing apparatus comprises an oven.
 7. A conveyorfor transporting product pans along a predetermined path having at leastone arcuate section comprising:a chain conveyor; a drive mechanism foradvancing said chain conveyor along said predetermined path; a pluralityof grids coupled to said chain conveyor at predetermined intervals forsupporting said product pans as said product pans move along saidpredetermined course; a plurality of magnets for securing product pansto the grids; a plurality of magnet supports coupled to said grids, saidsupports being adapted to allow said magnets to move a limited distancein a horizontal direction relative to said grid.
 8. The conveyor ofclaim 7 wherein a pair of said magnets carried by adjacent gridsmaintain a substantially constant position relative to a single productpan retained by said pair of magnets as said adjacent supporting gridschange position relative to each other.
 9. The conveyor of claim 7wherein each said grid comprises at least one transverse portionextending substantially perpendicular to said conveyor chain and atleast one parallel portion extending substantially parallel to saidconveyor chain, said parallel portion being coupled to said transverseportion.
 10. The conveyor of claim 7 wherein said conveyor is adaptedfor use in a proofer.
 11. The conveyor of claim 7 wherein said conveyoris adapted for use in an oven.
 12. The conveyor of claim 7 wherein saidconveyor is adapted for use in an oven.
 13. A conveyor for transportingproduct pans along a predetermined path having at least one arcuatesection comprising:a chain conveyor; a drive mechanism for advancingsaid chain conveyor along said predetermined path; a plurality ofmagnets for retaining said product pans as said product pans aretransported through said predetermined path; a plurality of gridscoupled to said chain conveyor at predetermined intervals for carryingsaid magnets, each said grid comprising at least one transverse portionextending substantially perpendicular to said conveyor chain and atleast one parallel portion extending substantially parallel to saidconveyor chain, said parallel portion being coupled to said transverseportion, said grids being adapted to allow a pair of said magnetscarried by adjacent grids to move relative to the grids to maintain aconstant position relative to a single product pan retained by said pairof magnets as said adjacent supporting grids change position relative toeach other as said adjacent grids move through said arcuate portion ofsaid predetermined path.
 14. The conveyor of claim 13 wherein saidconveyor is adapted for use in a proofer.
 15. A magnetic grid system foruse with a center driven chain conveyor, said grid system comprising:aplurality of grids coupled to said conveyor chain at predeterminedintervals; a plurality of magnets, each of said magnets mounted on oneof said grids for securing food conveying pans for transport around saidpredetermined course, said magnets being mounted for limited movement ina horizontal plane relative to said grid.
 16. The grid system of claim15 wherein a pair of said magnets carried by adjacent grids maintain asubstantially constant position relative to a single product panretained by said pair of magnets as said adjacent supporting gridschange position relative to each other.
 17. The grid system of claim 15wherein each said grid comprises at least one transverse portionextending substantially perpendicular to said conveyor chain and atleast one parallel portion extending substantially parallel to saidconveyor chain, said parallel portion being coupled to said transverseportion.
 18. The grid system of claim 15 further comprising magnetretainers for movably retaining said magnets relative to said grids. 19.The grid system of claim 15 wherein said food processing apparatuscomprises a proofer.
 20. The grid system of claim 15 wherein said foodprocessing apparatus comprises an oven.